PURPOSE: To improve responsiveness by replacing previously an instruction so as to execute measuring processing instead of the measuring point instructions of each position of the entry point and the exit point of a module desired to measure, and summing up the time of passing repeatedly through the corresponding measuring point.

CONSTITUTION: The instruction is replaced previously to the measuring point, and the time of passing through this measuring point is recorded in a measuring processing stage, and after returning the instruction to the original instruction, the corresponding measuring point instruction is executed. Then, if the processing of all processing is not finished, the processing is returned to a first instruction replacing stage, and the measuring processing is made capable of being executed when the processing comes again to the measuring point. Accordingly, the time is recorded every time the processing passes through the same measuring point by some number of times, and the time, for instance, from the entry point to the exit point is calculated in a record totalling/ calculating processing stage 8. Thus, the responsiveness can be improved.